US3139401A - Method for removing rust from water softeners - Google Patents

Method for removing rust from water softeners Download PDF

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Publication number
US3139401A
US3139401A US164624A US16462462A US3139401A US 3139401 A US3139401 A US 3139401A US 164624 A US164624 A US 164624A US 16462462 A US16462462 A US 16462462A US 3139401 A US3139401 A US 3139401A
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ion exchange
rust
exchange resin
water
regeneration
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US164624A
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Clifford C Hach
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Hach Co
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Hach Co
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J49/00Regeneration or reactivation of ion-exchangers; Apparatus therefor
    • B01J49/60Cleaning or rinsing ion-exchange beds

Description

United States Patent 3,13,41 METHOD FOR REMOVING RUST FROM WATER SOFTENERS Clifford C. Hash, Antes, Iowa, assignor to Hach Chemical Company, Arnes, Iowa, a corporation of iowa No Drawing. Filed Jan. 5, 1962, Ser. No. 164,624 7 Claims. (Cl. 21tl3tl) The present invention relates to an improved method for dissolving and removing rust from ion exchange apparatus such as water softeners; More specifically, the invention relates to a method finding particular, but not necessarily exclusive use, in removing rust from the resin contained in ion exchange type water softeners which include a brine tank holding a supply of brine for use in automatically regenerating the ion exchange resin in the apparatus.

The inventipn has, as its principal objective, the removal of rust accumulations from ion exchange equipment, such as water softening equipment and from the ion exchange resins used in that equipment, the eificiency of which is reduced as rust collects. A more specific ob jective resides in the removal of rust from such equipment when used with a brine tank containing a supply of brine for use during the automatic regeneration of the equipment.

Another object of the present invention is to provide an improved method for removing rust from water softening equipment of the automatic regenerating type.

Other objects and advantages of the present invention will become apparent as the following description proceeds. While the present invention is embodied in a process finding particular, but not necessarily exclusive, utility for removing rust from automatically regenerated water softening equipment, certain modifications and alternative constructions will doubtless occur to those skilled in the art upon reading the following specification. It is nevertheless the intention to cover those modifications, alternative constructions, equivalents, and uses falling within the spirit and scope of the invention as expressed in the appended claims.

The zeolite or ion exchange process of softening water has been very widely used with satisfactory results. By such a process calcium and magnesium, and to some extent iron, ions are removed from hard water and are replaced by an equivalent quantity of sodium ions. The chemical reactions of such ion exchange process may be stated as follows:

where M=metal ion such as calcium, magnesium, or iron, and Ze=zeolite or ion exchange resin.

The above process takes place during the water softening cycle and continues until the ion exchange resin has been exhausted. At that time it is necessary to regenerate or recharge the resin so that it is capable of further softening action. This is usually accomplished by treating the spent resin with a strong salt brine, usually a sodium chloride brine, although other sodium salts such as the sodium halogens can be employed. Treatment with a strong brine is capable of reversing the softening action as follows:

The metal ions (M++) are then washed out of the bed by the fiow of the salt brine.

One trouble which often occurs as the result of the continued use of the water softener, particularly in certain areas of the country, is the accumulation of iron rust in the equipment. This accumulation of rust occurs with the rust both in a loose form and in a form firmly attached ICC to the particles of the ion exchange materials. This results in a number of difiiculties, including (1) a reduction of ion exchange capacity as a result of the coating and clogging of the porous ion exchange resin particles with rust; (2) the occurrence of objectionable amounts of rust in the softener efiluent water; and (3) accumulation water varies widely according to location, iron generally is present in an amount less than about 10 parts: per million, although higher amounts might occasionally be encountered.

Soluble iron in the ferrous form is removed from the water by the above described ion exchange process.

However, when water containing ferrous iron is exposed to air, the iron is oxidized to ferric iron (Fe+++) by the action of atmospheric oxygen. In theferric form, iron in the water is converted to ferric hydroxide or rust. Rust is very insoluble and thus the water becomes rusty, and rust deposits appear on fittings, fixtures, and the like. In any water system there is invariably some leakage of air into the water so that iron is oxidized and rust is produced. Referring specifically to Water softening equipment, ferric iron rust may be produced inside the softener itself aswell as in other parts of the system so that ultimately a softener becomes fouled with rust when it is used on water containing iron.

Salt brine has in itself little capability for removing iron rust from a water softener bed. Most softeners, therefore, are subject to a very annoying and serious rust fouling problem. Many chemical agents have been proposed and used to clean rust from softener beds. In most instances these agents are of the type which can be added to the salt brine used to regenerate the softener which components will dissolve the accumulated rust and thus rinse it away during the regeneration process. One of the most successful compounds which has been used in this way is sodium hydrosulfite (Na S O Sodium hydrosulfite is subject to oxidation by atmospheric oxygen and is unstable when dissolved in water.

For these reasons this compound is not suitable by itself as an additive to salt for use with water softeners which have a brine storage tank system. In such systems, which are usually employed with automatically regenerating Water softeners, the brine is made and stored ready for use. If sodium hydrosulfite is added to this brine, it rapidly deteriorates and becomes ineffective for removing rust from the water softener.

In accordance with the present invention, there is provided an improved process for utilizing hydrosulfite salts, for example sodium hydrosulfite, to remove or dissolve rust from an ion exchange apparatus such as a water softener. To illustrate this process, sodium bisulfite (Nell-I50 or sodium metabisulfite (Na S O both of which are soluble in water or salt brine and form solutions which are quite stable, are dissolved in the brine storage tank of an automatic regenerating water softening system. A tank containing granules or porous sponge blocks of zinc or other metal is provided in the brine conduit between the brine tank and the water softener through which the brine is carried when it is required for use in regeneration. When the brine containing dissolved sodium bisulfite or sodium metabisulfite salts passes through the tank of zinc or other metal, these compounds Patented June 30, 1964- react with the metal to form-sodium hydrosulfite accordingtothe following equations:

2NaHSO +Zn Na S +Zn(OH) 2SzO 2Q+ n zSz 4+ H)2 Theabove process takes place in a satisfactory manner andgqlii terapidly when -a small amount of sodium bisulfite isjaddedtothe .salt and a brine is then made. For

aswell canbe employed and will appreciate that the type of metalisnot critical so long as the desired result, namely, the' production of a sufiicient amount ofhydrosulfite is accomplished for the purpose of removing rustfrom the apparatus.

The brine. containing thev freshly generated hydrosulfite .salt,is then passed through the water softener in the usuaLmanner in which it regenerates the ion exchange materialand at the same time. dissolves any iron rust which is present in the manner described above.

A It will also be appreciated that when sodium chloride is employed it is advantageous to use sodium bisulfite or,

sodium ,metabisu lfite. Again, it is important only that there be present in-the brine bisulfite or metabisulfite ions andtheparticular metal ion of the bisulfite salt is not critical. Those skilled in the. art will further appreciate that thebisulfites and metabisulfites of the various alkali metals such aslithium, sodium, potassium, rubidium, and cesium, and the various alkaline-earth metals, such as barium and calcium and strontium can be employed to advantage. i

The amount of bisulfite salt added to the brine will be determined therust content of the Water being treated, by the conditiono f the softening equipment, and in general by the economics of the process. Once a system is operating with therust remover, only small amounts will be required. For fouledsystems,v the amount required initiallywill be. somewhat larger, although as rust is removedithelamount of rust remover can be reduced. For

the most part the amounts of rust. remover required will v depend on the system being treated and no specific statement of amounts tobe employed can be made. This can be easily determined by one skilled in the art in light of the foregoing description.

I claim asmy invention:

1. In the process which comprises passage of a liquid overa bed-of ion exchange resin to remove metal ions therefrom and intermittentregeneration of the bed of ion exchange resin by contact with a regeneration solution, the improvement whereby iron containing deposits resulting from the presence in said liquid of iron-containing constituents, are removed from the ion exchange resin at the time the same is regenerated which comprises (1) admixing with the regeneration solution a compound selected from the group consisting of alkali and alkali earth metal sulfites, bisulfites, metabisulfites and mixtures thereof and (2) contacting the regeneration solution containing said compound with a metal selected from the group consisting of zinc, aluminum, magnesium and alloys and mixtures thereof having substantial surface area prior to introducing the samev to the bed of ion exchange resin for regeneration thereof.

2. The process of claim 1 wherein the. treatment of the liquid by contact with the .bed of ion exchange resin and the intermittent regenerationof the resin are carried out:

on an automatic basis and the regeneration solution is introduced to the ion exchange bed from a reservoir connected to the bed of ion exchange. resin byautomatically operated valve and pump means.

3. The'process of claim 1 wherein the regeneration solution comprises. sodium chloride brine.

4. The methodof claim 1 wherein the. compound selected from the group consisting of the alkali and alkaline earth metal sulfites, bisulfites, metabisulfites and mixtures thereof is admixed with the regeneration solution in an,

amount of from about 0.5% to about 5% by weight.

5. The method-of claim, 1 wherein the metal, with which the regeneration solution is contacted prior to introduction of said solution to the bed of ion exchange resin during the regeneration cycle, is zinc.

6. The process of claim 5 wherein the zinc is present in a finely divided state.

. 7. The process ofclaim 1 wherein the liquid from which the metal ions are removed is water, the compound admixedwith the regeneration solution is selected from the group consisting of sodium sulfite, sodium bisulfite, sodium metabisulfite, and mixtures thereof, the regenera tion solution is a sodium chloride brine and the metal with which the regeneration .solutionis contacted prior to introduction to the bed of ion exchange resin during the regeneration cycleis particulate zinc.

References Cited in the file of this patent.

' UNITED STATES PATENTS OTHER REFERENCES;

Chem. Abstracts, vol. 49, October-November 1955, page 14239b.

Liberation of Iron From Zeolite, Kitsuta (Japan 5370 (1954 Matsubara).

Claims (1)

1. IN THE PROCESS WHICH COMPRISES PASSAGE OF A LIQUID OVER A BED OF ION EXCHANGE RESIN TO REMOVE METAL ION THEREFROM AND INTERMITTENT REGENERATION OF THE BED OF ION EXCHANGE RESIN BY CONTACT WITH A REGENERATION SOLUTION THE IMPROVEMENT WHEREBY IRON CONTAINING DEPOSITS RESULT ING FROM THE PRESENCE IN SAID LIQUID OF IRON-CONTAINING CONSTITUENTS, ARE REMOVED FROM THE ION EXCHANGE RESIN A THE TIME THE SAME IS REGENERATED WHICH COMPRISES (1) AD MIXING WITH THE REGENERATION SOLUTION A COMPOUND SE LECTED FROM THE GROUP CONSISTING OF ALKALI AND ALKALI EARTL METAL SULFITES, BISULFITES, METABISULFITES AND MIXTURES THERE OF AND (2) CONTACTING THE REGENERATION SOLUTION CONTAIN ING SAID COMPOUND WITH A METAL SELECTED FROM THE GROUP CONSISTING OF ZINC, ALUMINUM, MAGNESIUM AND ALLOYS AND MIXTURES THEREOF HAVING SUBSTANTIAL SURFACE AREA PRIOR TO INTRODUCING THE SAME TO THE BED OF ION EXCHANGE RESIN FOR REGENERATION THEREOF.
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Cited By (51)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3255106A (en) * 1963-11-20 1966-06-07 Union Tank Car Co Water conditioning system
US3262876A (en) * 1963-07-05 1966-07-26 Calgon Corp Cleaning ion exchange resins
US3308955A (en) * 1964-02-04 1967-03-14 Meadowbrook Company Apparatus for injecting into water softening systems
US3470067A (en) * 1967-09-19 1969-09-30 Pfizer & Co C Concentration and purification of viruses from particulate magnetic iron oxide-virus complexes
US3623992A (en) * 1970-06-01 1971-11-30 Diamond Crystal Salt Co Rock salt composition and method
US3984313A (en) * 1973-09-18 1976-10-05 Chemical Separations Corporation Preferential removal of ammonia and phosphates
US4151079A (en) * 1978-06-05 1979-04-24 Nalco Chemical Company Regeneration of ion exchange resins
US4664811A (en) * 1985-07-01 1987-05-12 Nalco Chemical Company Prevention of iron fouling of ion exchange resins
US20050109692A1 (en) * 1998-09-25 2005-05-26 Fufang Zha Apparatus and method for cleaning membrane filtration modules
US20070007205A1 (en) * 2003-08-29 2007-01-11 Johnson Warren T Backwash
US20070075021A1 (en) * 2003-11-14 2007-04-05 U.S. Filter Wastewater Group, Inc. Module cleaning method
US20070181496A1 (en) * 2004-03-26 2007-08-09 Zuback Joseph E Process and apparatus for purifying impure water using microfiltration or ultrafiltration in combination with reverse osmosis
US20080053923A1 (en) * 2004-09-14 2008-03-06 Siemens Water Technologies Corp. Methods And Apparatus For Removing Solids From A Membrane Module
US20080156745A1 (en) * 2004-09-15 2008-07-03 U.S. Filter Wastewater Group, Inc. Continuously Variable Aeration
US20080203016A1 (en) * 2004-12-24 2008-08-28 Siemens Water Technologies Corp. Cleaning in Membrane Filtration Systems
US20080203017A1 (en) * 2005-04-29 2008-08-28 Siemens Water Technologies Corp A Corporation Chemical Clean For Membrane Filter
US20080237125A1 (en) * 2001-11-16 2008-10-02 Paul Martin Gallagher Method of cleaning membranes
US20080257822A1 (en) * 2005-12-09 2008-10-23 Warren Thomas Johnson Reduced Backwash Volume Process
US20090001018A1 (en) * 2006-01-12 2009-01-01 Fufang Zha Operating Strategies in Filtration Processes
US20090255873A1 (en) * 2006-08-31 2009-10-15 Bruce Gregory Biltoft Low pressure backwash
US7632439B2 (en) 2002-02-12 2009-12-15 Siemens Water Technologies Corp. Poly(ethylene chlorotrifluoroethylene) membranes
US20100000941A1 (en) * 2004-12-24 2010-01-07 Siemens Water Technologies Corp. Simple gas scouring method and apparatus
US20100012585A1 (en) * 2007-02-16 2010-01-21 Fufang Zha Membrane filtration process and design
US20100051545A1 (en) * 2007-04-04 2010-03-04 Warren Thomas Johnson Membrane module protection
US20100170847A1 (en) * 2007-05-29 2010-07-08 Fufang Zha Membrane cleaning using an airlift pump
US20100191377A1 (en) * 2006-10-24 2010-07-29 Smith George W Infiltration/inflow control for membrane bioreactor
US20100200503A1 (en) * 2007-06-28 2010-08-12 Fufang Zha Cleaning method for simple filtration systems
US20100300968A1 (en) * 2009-06-02 2010-12-02 Siemens Water Technologies Corp. Membrane cleaning with pulsed gas slugs
US20100326906A1 (en) * 2007-04-02 2010-12-30 Barnes Dennis J infiltration/inflow control for membrane bioreactor
US20110056522A1 (en) * 2009-06-11 2011-03-10 Peter Zauner Method of cleaning membranes
US20110100907A1 (en) * 2007-05-29 2011-05-05 Siemens Water Technologies Corp. Membrane cleaning with pulsed arilift pump
US7938966B2 (en) 2002-10-10 2011-05-10 Siemens Water Technologies Corp. Backwash method
US20110127209A1 (en) * 2008-07-24 2011-06-02 Siemens Water Technologies Corp. Frame System for Membrane Filtration Modules
US20110132826A1 (en) * 2008-08-14 2011-06-09 Siemens Water Technologies Corp. Block Configuration for Large Scale Membrane Distillation
US20110139715A1 (en) * 2008-08-20 2011-06-16 Siemens Water Technologies Corp. Membrane System Backwash Energy Efficiency
US20110192783A1 (en) * 2001-04-04 2011-08-11 Siemens Industry, Inc. Potting Method
US8048306B2 (en) 1996-12-20 2011-11-01 Siemens Industry, Inc. Scouring method
US8182687B2 (en) 2002-06-18 2012-05-22 Siemens Industry, Inc. Methods of minimising the effect of integrity loss in hollow fibre membrane modules
US8512568B2 (en) 2001-08-09 2013-08-20 Siemens Industry, Inc. Method of cleaning membrane modules
US8790515B2 (en) 2004-09-07 2014-07-29 Evoqua Water Technologies Llc Reduction of backwash liquid waste
US8858796B2 (en) 2005-08-22 2014-10-14 Evoqua Water Technologies Llc Assembly for water filtration using a tube manifold to minimise backwash
US9022224B2 (en) 2010-09-24 2015-05-05 Evoqua Water Technologies Llc Fluid control manifold for membrane filtration system
US9533261B2 (en) 2012-06-28 2017-01-03 Evoqua Water Technologies Llc Potting method
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US9764288B2 (en) 2007-04-04 2017-09-19 Evoqua Water Technologies Llc Membrane module protection
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US9815027B2 (en) 2012-09-27 2017-11-14 Evoqua Water Technologies Llc Gas scouring apparatus for immersed membranes
US9914097B2 (en) 2010-04-30 2018-03-13 Evoqua Water Technologies Llc Fluid flow distribution device
US9925499B2 (en) 2011-09-30 2018-03-27 Evoqua Water Technologies Llc Isolation valve with seal for end cap of a filtration system
US9962865B2 (en) 2012-09-26 2018-05-08 Evoqua Water Technologies Llc Membrane potting methods
US10322375B2 (en) 2015-07-14 2019-06-18 Evoqua Water Technologies Llc Aeration device for filtration system

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US136770A (en) * 1873-03-11 Improvement in the preparation of indigo for dyeing and printing
CA629715A (en) * 1961-10-24 E. Schulze Robert Iron removal unit and process and means for treating ion exchange materials

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US136770A (en) * 1873-03-11 Improvement in the preparation of indigo for dyeing and printing
CA629715A (en) * 1961-10-24 E. Schulze Robert Iron removal unit and process and means for treating ion exchange materials

Cited By (78)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3262876A (en) * 1963-07-05 1966-07-26 Calgon Corp Cleaning ion exchange resins
US3255106A (en) * 1963-11-20 1966-06-07 Union Tank Car Co Water conditioning system
US3308955A (en) * 1964-02-04 1967-03-14 Meadowbrook Company Apparatus for injecting into water softening systems
US3470067A (en) * 1967-09-19 1969-09-30 Pfizer & Co C Concentration and purification of viruses from particulate magnetic iron oxide-virus complexes
US3623992A (en) * 1970-06-01 1971-11-30 Diamond Crystal Salt Co Rock salt composition and method
US3984313A (en) * 1973-09-18 1976-10-05 Chemical Separations Corporation Preferential removal of ammonia and phosphates
US4151079A (en) * 1978-06-05 1979-04-24 Nalco Chemical Company Regeneration of ion exchange resins
US4664811A (en) * 1985-07-01 1987-05-12 Nalco Chemical Company Prevention of iron fouling of ion exchange resins
US8048306B2 (en) 1996-12-20 2011-11-01 Siemens Industry, Inc. Scouring method
US20050109692A1 (en) * 1998-09-25 2005-05-26 Fufang Zha Apparatus and method for cleaning membrane filtration modules
US8518256B2 (en) 2001-04-04 2013-08-27 Siemens Industry, Inc. Membrane module
US20110192783A1 (en) * 2001-04-04 2011-08-11 Siemens Industry, Inc. Potting Method
US8512568B2 (en) 2001-08-09 2013-08-20 Siemens Industry, Inc. Method of cleaning membrane modules
US20080237125A1 (en) * 2001-11-16 2008-10-02 Paul Martin Gallagher Method of cleaning membranes
US7632439B2 (en) 2002-02-12 2009-12-15 Siemens Water Technologies Corp. Poly(ethylene chlorotrifluoroethylene) membranes
US8182687B2 (en) 2002-06-18 2012-05-22 Siemens Industry, Inc. Methods of minimising the effect of integrity loss in hollow fibre membrane modules
US7938966B2 (en) 2002-10-10 2011-05-10 Siemens Water Technologies Corp. Backwash method
US8268176B2 (en) 2003-08-29 2012-09-18 Siemens Industry, Inc. Backwash
US20070007205A1 (en) * 2003-08-29 2007-01-11 Johnson Warren T Backwash
US20070075021A1 (en) * 2003-11-14 2007-04-05 U.S. Filter Wastewater Group, Inc. Module cleaning method
US8808540B2 (en) 2003-11-14 2014-08-19 Evoqua Water Technologies Llc Module cleaning method
US20070181496A1 (en) * 2004-03-26 2007-08-09 Zuback Joseph E Process and apparatus for purifying impure water using microfiltration or ultrafiltration in combination with reverse osmosis
US8758621B2 (en) 2004-03-26 2014-06-24 Evoqua Water Technologies Llc Process and apparatus for purifying impure water using microfiltration or ultrafiltration in combination with reverse osmosis
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US20080257822A1 (en) * 2005-12-09 2008-10-23 Warren Thomas Johnson Reduced Backwash Volume Process
US20090001018A1 (en) * 2006-01-12 2009-01-01 Fufang Zha Operating Strategies in Filtration Processes
US20090255873A1 (en) * 2006-08-31 2009-10-15 Bruce Gregory Biltoft Low pressure backwash
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US20110139715A1 (en) * 2008-08-20 2011-06-16 Siemens Water Technologies Corp. Membrane System Backwash Energy Efficiency
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US9604166B2 (en) 2011-09-30 2017-03-28 Evoqua Water Technologies Llc Manifold arrangement
US9533261B2 (en) 2012-06-28 2017-01-03 Evoqua Water Technologies Llc Potting method
US9764289B2 (en) 2012-09-26 2017-09-19 Evoqua Water Technologies Llc Membrane securement device
US9962865B2 (en) 2012-09-26 2018-05-08 Evoqua Water Technologies Llc Membrane potting methods
US9815027B2 (en) 2012-09-27 2017-11-14 Evoqua Water Technologies Llc Gas scouring apparatus for immersed membranes
US10322375B2 (en) 2015-07-14 2019-06-18 Evoqua Water Technologies Llc Aeration device for filtration system

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